The present invention relates to the art of biological indicators. It finds particular application in conjunction with spore inoculated elements used for indicating the completeness of a sterilization process and will be described with particular reference thereto.
Heretofore, various sterilization indicating systems have been provided. The systems generally included an element, e.g. a pad or strip, which was inoculated with a spore or other microorganism. In some systems, the pad was mounted in a container and connected with the container exterior by a tortuous path or otherwise. The container was disposed such that during a gas or high pressure steam sterilization process, the pad was subject to substantially the same sterilizing conditions by gas or high pressure steam that penetrates the tortuous path as the articles being sterilized. At the end of the sterilizing operation, the tortuous path was closed, a glass ampule containing a culture medium was fractured, and the pad and culture medium were brought together. After an appropriate incubation period, the culture medium was examined for evidence of growth of the inoculated microorganisms. A lack of microorganism growth was indicative of sterilization and growth of the microorganisms was indicative that the sterilization process was not complete. See, for example, U.S. Pat. Nos. 4,461,837 and 4,743,537.
A disadvantage of the prior art sterilization indicating systems was that the element containing the spores or other microorganisms was often times a spore strip pad. The spores, when contacted by sterilant or disinfectant mediums, could potentially be dislodged.
These problems have been addressed by placing the inoculated element in an envelope of sorts, the envelope being constructed from a semi-porous or non-porous material, and usually from paper. The paper, however, was easily dissolved when using a liquid sterilant or disinfectant or made it very difficult to transfer asceptically to culture medium, thus requiring that the strip be removed from the envelope prior to use, making it very difficult to transfer the strip asceptically to the culture medium. If the spore containing element or spore strip was removed from the envelope, however, the potential problem such as the spores being washed off of the strip may again be encountered.
The present invention provides a new and improved spore containing element which is suitable for use in steam, gas, or liquid sterilant systems, yet overcomes the above-referenced problems.